Dampening apparatus for offset process printing presses



NOV. 22, 1960 5, ERZlNGER 2,960,929

DAMPENING APPARATUS FOR OFFSET PROCESS PRINTING PRESSES Filed June 15, 1959 2 Sheets-Sheet 1 FIG. 5. 4o

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DANIPENING APPARATUS FOR GFFSET PROCESS 5 PRINTING PRESSES Leonard G. Erzinger, 17 03 SummerfieldAve., Brooklyn 27, N.Y.

Filed .Inne 15, 1959, Ser. No. 820,414

2 Claims. (Cl. 1G1147) This invention relates to an improved dampening ap- 15 paratus for offset process printing presses. It constitutes an improvement over the apparatus which is shown and described in my copending patent application Serial No. 709,703, filed January 17, 1958, now US. Patent No. 2,897,753.

Much of the subject matter of the present application may be found in my said copending application, and reference may be made to said copending application for details which are omitted from the present application by reason of the fact that they do not relate directly to the improvement herein claimed.

It is known that during the operation of a lithographic printing press the impression, blanket and plate cylinders are in contact, transfering the image or impression to the paper. It is also known that duiing such operation 0 the ink and water supply systems function to transfer, deliver or feed the required quantities of ink and water to the press. By the same token, a paper feeding mechanism also functions during the operation of the press to feed paper to the impresion and blanket cylinders.

From time to time the paper feed is interrupted, either by manual or automatic means. For example, when misfed sheets of paper enter the press, the cylinders will separate and the ink rollers will leave the plate. However, the water supply system remains in operation and continues to feed water to the plate. This is known in the industry as a trip-up.

The principal object of this invention is the provision of water feed control means which controls, either manually or automatically, the feeding of water to the press.

The water control means herein described and claimed performs the following functions: It permits a full flow of water to the press during normal operation thereof; it meters the flow and reduces it to a predetermined eX- 0 tent when required by certain operating conditions, as for example to establish a proper ink and water balance or when a trip-up occurs; and it completely shuts olf the supply of water to the press at such time as the press is at rest or operating without printing.

The water flow control means which is herein claimed comprises, in effect, an elongated rake which extends the full length of the water supply system, or the full range of its operation. As is the case with more conventional rakes, the rake herein claimed is provided with an 60 elongated horizontal bar and a plurality of vertically extending teeth. In the preferred form of this invention the spaces between the teeth are of approximately the same width as the teeth themselves. Also in the preferred form of this invention the teeth project downwardly from the horizontal bar, but it will be understood that upwardly projecting teeth would perform equally as well.

As is disclosed in my copending patent application, a water feed nozzle is mounted for reciprocating movement along a horizontal path, and during operation of the press the nozzle moves from side to side, continuously feeding a spray of water to the ink system. In the present invention the rake is situated between the nozzle and the ink rollers, but it is vertically adjustable. In one position, the horizontal bar of the rake is situated at the same level as the nozzle, and it functions as a barrier preventing the water from reaching the ink rollers. A run-off trough is located below the nozzle and the rake to catch the water which thus impinges upon the horizontal bar. In a second position, the rake is elevated to the point where only its teeth are disposed between the nozzle and the ink rollers. When the rake is in such position, only half of the water fed from the nozzle reaches the ink rollers, the teeth blocking the rest of the water. It will be understood that the teeth could be made wider and the spaces between them narrower, or vice versa, to vary the relative supply of water reaching the ink rollers. In a third position, the entire rake would be elevated to the extent necessary to clear the nozzle, thereby permitting a full flow of water to reach the ink rollers.

Another important feature of this invention is the provision of water blocking clips which may be removalbly mounted upon the rake. It is known that, during the operation of a printing press of the character under discussion, a need sometimes develops for a diminished flow of water at specific points along the plate. These removable clips are accordingly placed upon the rake at such specific points in order to block the flow of water which would otherwise reach such points. In effect, these clips function in the manner of additional, temporary teeth installed in the rake at any desired locations thereon.

The invention is illustrated in the accompanying drawing in which:

Fig. 1 is a fragmentary, partly schematic, vertical section through an oifset printing press embodying the dampening apparatus herein claimed.

Fig. 2 is a fragmentary top view of the dampening apparatus.

Fig. 3 is a side View, partly in vertical section, on the line 3-3 of Fig. 2.

Fig. 4 is a vertical section through the dampening apparatus taken on the line 4-4 of Fig. 2.

Fig. 5 is another vertical section taken on the line 55 of Fig. 2.

Fig. 6 is a fragmentary vertical section on the line 6-6 of Fig. 2.

Fig. 7 is a circuit diagram showing the circuits'ofthe water feeding and feed control apparatus.

Referring now to the details of the drawing, it will be noted that a plate cylinder 10 is provided, together with a rubber-covered cylinder 12, commonly known as a blanket cylinder, and a plurality of' inking rollers 14; 16, 18 and 20 respectively. Mounted on plate cylinder 10 is a conventional offset printing plate 22. The offsetprinting plate has a photographic ima e applied thereto and the chemical action of the photographic image area and the surrounding area is such that the ink adheres 3 only to the photographic image while the area surrounding the image receives water and repels the ink. The ink is transfered from the offset printing plate to the blanket cylinder 12 and thence to the paper. This procedure is conventional.

The apparatus for wetting the offset plate 22 includes an elevated container or reservoir 24, containing acidulated water 30, a hose 26 leading downwardly from the outlet port of said reservoir, and a discharge nozzle or jet 28. Nozzle 28 is situated opposite inking roller 18 and it will be understood that the Water may be sprayed from said nozzle directly upon said inking roller (or upon any other roller in the inking system) which carit to the offset printing plate 22. The flow of water through nozzle 28 may be controlled by raising or lowering container 24 relative to said nozzle. This may be done by means of an adjustable bracket 32 which supports said container on a vertical stand 34. A thumbscrew 36 adjustably secures said bracket to said stand and the bracket may be raised or lowered as desired to raise or lower container 24.

It will be understood from my copending patent application that nozzle 28 is supported by a suitable bracket 38 in operative position relative to roller 18. A trough '40, paralleling roller 18 may be provided below nozzle 28 to catch the water that may drip from the nozzle as Well as the water which the rake blocks as above .de scribed. Stand 34 and bracket 38 are supportedon a carriage 50. As appears from my copending application, carriage 50 is adapted to move in reciprocating fashion on horizontal rails 60 and 62 respectively, supported on frames 64 and 66 of the printing press. The carriage accordingly carries the nozzle along the entire length of inking roller 18, first in one direction and then in the opposite direction. This is accomplished by means of an endless chain 70 which rides on a pair of sprockets 72 and 74 respectively, these sprockets being mounted on shafts 76 and 82. Shaft 82 is connected to a worm gear 84 which is in mesh with a worm 86 driven by electric motor 88. The chain is to be caused to move continuously in a given direction.

A single pin 90 projects laterally and horizontally from one of the links in the chain. A pair of vertically extending pins 92 and 94 are secured to carriage 50, pin 92 projecting downwardly from an elevated portion of said carriage, and pin 94 projecting upwardly from a lower portion of said carriage. It will be understood that horizontal pin 90 will engage vertical pin 92 and move the carriage leftwardly from its position shown in Fig. 3 and said horizontal pin 90 will then engage the second vertical pin 94, thereby moving the carriage rightwardly. This procedure continues and the carriage is moved from side to side during the entire operation of the machine.

A pair of vertical bars 100 are mounted on opposite sides of the machine for vertical movement in both directions. These bars are guided by means of bearing plates 102 and 104 and guide rollers 106, said bearing plates being supported on the frame of the machine. Journaled'into bearing plates 104 is a rocker shaft 108 and secured to said shaft are two arms 110 which engage pins 112 on the vertical bars 100. Another pair of arms 114 are secured to said rocker shaft 108 and they are situated to engage crosspins 116 and 118 mounted on the plungers of solenoids 120 and 122 respectively. When the solenoids are energized, arms 114 are pivoted upwardly in clockwise direction as viewed in Fig. 6 and arms 110 are also caused to pivot in the same direction as viewed in Fig. 4. This results in elevating bars' 100. The two solenoids and their respective arms 114 are so arranged that one of them will cause a greater angular movement of the rocker shaft than the other. The purpose of this will shortly become apparent.

Secured to the upper ends of vertical bars 100 is a rake 120. This rake comprises a horizontal bar 122 having a plurality of downwardly projecting, horizontally spaced teeth 124. As above indicated, in the preferred form of this invention the spaces 126 between teeth 124 are approximately of the same width as said teeth. It will now become apparent that when vertical bars 100 are in their lowermost positions, horizontal bar 122 of the rake Will be disposed immediately in front of nozzle 28 and it will serve as -a barrier preventing the water spray discharged from said nozzle from reaching the inking roller 18. When one of the solenoids is energized, namely solenoid 120 designated in Fig. 7 as the half stroke solenoid vertical bars 100 will be elevated only to the extent of moving horizontal bar 122 out of the path of the water discharging from the nozzle and moving teeth 124 into said path. Bearing in mind that the nozzle is mounted on a reciprocating carriage and is therefore moved from side to side, it will be understood that the flow of water will be interrupted by said teeth while remaining free to reach the inking roller 18 through spaces 126 between the teeth. When solenoid 122 is energized, said solenoid being designated in Fig. 7 as the full stroke solenoid, vertical bars 100 will be elevated to the extent necessary to move the entire rake out of the path of the water discharging from the nozzle. This process is shown in Fig. 5 and it will be understood that the nozzle is now entirely unobstructed and its full flow will impinge upon inking roller 18.

Reference to Fig. 7 will disclose the fact that a switch 130 controls the motor, a second switch 132 controls the half stroke solenoid 120 and a third switch 134 controls the full stroke solenoid 122. Switches 130 and 132 are manually operated switches, while switch 134 is an automatic limit switch actuated by a reciprocating part of the impression mechanism. A fourth switch 136 is provided and it will be noted that this is a manually controlled switch which controls the full stroke solenoid. A pilot light 138 may be incorporated into the circuit which energizes the half stroke solenoid.

It will now be understood that when it is desired to block off specific areas on inking roller 18 from the flow of water, clips 140 are detachably mounted on rake 120. These clips function in the manner of additional teeth on the rake and they may be used to cover selected spaces 126 between the permanent teeth 124 of the rake.

The foregoing is illustrative of a preferred form of this invention and it will be understood that modifications and variations may be incorporated therein within the broad principles of the invention and the broad scope of the claims.

I claim:

1. In a photo-offset printing press, a plurality of inking rollers, said rollers being disposed in parallel relation to each other, all on horizontal axes of rotation, a horizontally movable water feed means mounted adjacent at least one of said rollers and adapted to feed water thereto, and a horizontally extending rake situated adjacent said roller and said water feed means, said rake being provided with a horizontally extending bar element and a plurality of vertically extending, horizontally spaced teeth projecting from said bar element, said rake being mounted on vertically movable supports for movement into three positions which may be assumed selectively,

said rake being movable into one of said positions between said water feed means and said inking roller wherein said bar element serves as a barrier preventing the water fed by the Water feed means from reaching said roller, said rake being movable into a second of said positions between said water feed means and said roller, wherein the teeth projecting from said bar are disposed in the path of the water, said teeth serving as barriers preventing the water which impinges upon them from reaching said'roller, the spaces between said teeth serving as passages for the remainder of the water fed by said water feed means, enabling said water to reach the roller,

thereby permitting a partial flow of Water to the roller, and said rake being movable into the third of said positions wherein both its bar and its teeth are entirely removed from the path of the water from the water feed means to the roller, thereby permitting a 'full flow of water to reach the roller.

2. In a photo-offset printing press in accordance with claim 1, at least one removable clip provided on said rake at a selected location thereon, said clip extending across at least one space between the teeth of the rake and being thereby adapted to function as a barrier to the water which would otherwise pass from said water feed means to said inking roller through said space when the rake occupies the second of its three positions.

References Cited in the file of this patent UNITED STATES PATENTS 2,178,583 Grembecki Nov. 7, 1939 2,389,730 Iler Nov. 27, 1945 2,678,001 Davidson May 11, 1954 2,791,174 Koch May 7, 1957 FOREIGN PATENTS 175,956 Austria Sept. 10, 1953 

